Motor-pump attachment for foot pump dental chairs



1952 E. P. SCHWARTZ ETAL 2,536,441

MOTOR PUMP ATTACHMENT FOR FOOT PUMP DENTAL CHAIRS 2 SHEETSSHEET 1 Filed March 28, 1946 FIG.1.1..

1952 E. P. SCHWARTZ ET AL 2,

MOTOR PUMP ATTACHMENT FOR FOOT PUMP DENTAL CHAIRS Filed March 28, 1946 2 SHEETS--SHEET 2 var/v 7-0 165 EU I? SCHWARTZ CHARLES W. MEYER Patented Feb. 19, 1952 UNITED STATES PATENT OFFICE MOTOR-PUMP ATTACHMENT FOR FOOT PUMP DENTAL CHAIRS Eli P. Schwartz, Clayton, and Charles W. Meyer, St.- Louis, Mo., assignors, by mesne assignments, to Bitter. Company, 1110., Rochester, N. Y., a corporation of Delaware Application March 28, 1946, Serial No. 657,828

(Cl. Gil-52) Claims. 1

This invention relates to improvements upon and attachments for vertically adjustable foot pump chairs such as are commonly used by den tists, surgeons, physicians and barbers, and which are raised and lowered hydraulically by means of foot-pumps operated by pedals as ex tended from the basal portions of the chairs.

The principal object of the invention is to pro vide and assemble in a single housing an electric motor, a suitable pump for drawing the oil or other hydraulic fluid contained within the base of the chair and transmitting same under pressure to the elevating cylinders and devices of the chair, an air dome for cushioning and absorbing pump pulsations, flexible hose or conduits and connections for drawing the fluid from the sump in the base of the chair up to and through the pump, whence it is forced back again under pressure to the said elevator or jack mechanisms and thence expelled after use back into the sump, mercury starting and limit switches, rubber mountings for the motor and pump, to absorb vibrations, and check valves to insure smooth action, and means for conveniently attaching the said housing and inclosed operating elements to the pedestal or base of the chair, for operating the hydraulic elevator cylinders or lifting jack thereof, all without changing o impairing in any manner the use or operation of the usual footpump apparatus of the chair, and without the need of any drilling or tapping, or the use of any special tools or expert mechanics.

Another object of the invention is to incorporate and mount in a single housing all needed elements and accessories for making the necessary additions to a regular foot-pump or pedal operated hydraulic elevator mechanism or lifting jackof such a chair, and without in any way changing same, for additionally providing the chair with a motor operated elevator mechanism or lifting jack, including means for releasably attaching the housing and contents to the pedestal or base of the chair, and means for connecting the inclosed elements and accessories with the originally provided hydraulic elevator mechanism or lifting jack of the chair for alternative use therewith, as may be desired.

A still further purpose of the invention is to provide an auxiliary power driven apparatus, completely contained within a specially formed housing removably attachable to the pedestal of a foot-pump chair of the kind described, and adapted to fit closely and symmetrically thereto, so that the entire assembly will assume a harmm nious and unitary appearance.

ill

With the stated objects in view, together with such other and additional objects and advantages as may appear from the following specifi cation, attention is now directed to the accord panying drawing, wherein: A

Figure 1 is a rear elevational view, showing the invention as applied to a foot or pedal operated pump chair of the kind referred to (the seat only of the chair being shown), showing a housing inclosing a major portion of the elements of the invention, as mounted upon the pedestal of the chair, parts being broken away for greater clearness.

Figure 2 is a horizontal, transverse section, on

" the line 2-2 of Figure 1.

Figure 3 is a side elevational view, viewed from the left side of the assembly, which assembly includes the chair pedestal with the housing mounted thereon containing the operating elements of the invention, the lid or cover of the housing bein removed.

Figure 4 is a perspective view of the mounting ring, which constitutes an essential element of the invention, and which is secured atop the upper and rotatably mounted basal section or portion of the pedestal of the chair, in lieu of the usual fiat cover or collar thereof, and through which mounting ring or cover collar the intake and discharge pipes involved in the invention as here set out, are passed perpendicularly downward, to the oil or fiuid sump of the apparatus.

Figure 5 is an enlarged sectional detail on the line 5--5' of Figure 3, elucidating the construction and assembly of the mercury starting switch as mounted within the rear end of the attachable housing.

Figure 6 is an enlarged sectional detail on the line 6-6 of Figure 2, showing the upper check valve as employed for passing the oil or hydraulic fluid from the motor driven pump through coriduits into the hydraulic lifting jack mechanism of the chair.

Figure 7 is a sectional detail on an enlarged scale,- taken on the line l--"! of Figure 2, showing the construction and mounting of the mercury limitswitch for automatically limiting the upward movement of the chair.

Figure 8 is a fragmentary sectional detail on an enlarged scale, on the line 8-8 of Figure 2, of the mercury limit switch assembly, as additionally shown in Figure 7, as mounted on the upper and rotatable basal section of the chair,

Figure 9 is an enlarged section on the line 9-=-9 of Figure 1, showing" in side elevation the lower parts and conduits of the hydraulically operated lifting jack mechanism of the chair, and showing the lower control Or check valve as added to the usual mechanism of the chair for incorporating the motor operated lifting apparatus thereon, the conventional parts of the assembly being indicated in dotted lines.

Figure 10 is a vertical, transverse section on the line llll of Figure 9.

Figure 11 is a schematic wiring diagram for the mercury starting and limit switches of the apparatus.

This invention is designed for application to and upon any conventional form of foot-pump dental chair, or the like, such as here indicated generally at 5 in the drawing, and which chair includes a heavy, hollow, downwardly and outwardly flared basal section 6, circular in cross section, upon which is superposed and rotatably mounted a similar hollow, flared and circular, secondary basal section I, the upper end of this assembly being thus considerably reduced diametrically, and the rotatable mounting being accomplished in any usual manner. The basal section 6 is completely inclosed at the bottom, as at Go, for there providing an oil or hydraulic fluid sump 8, the upper end of this section being open for receiving and rotatably engaging the lower, flared and open end of the secondary basal section 1. The basal section is also open at its upper end for reciprocably receiving and mounting the telescopically assembled elevator or jack cylinders 9 and I0, carrying the chair H at the upper end of cylinder l0. These elements are all constructed and assembled in the usual manner, and the cylinders 8 and ID are raised and lowered hydraulically in the usual way through operation of the spring-set footpump i2 (Figures 2 and 9) by the pedal E3, the chair lowering operation being accomplished by depressing another spring-set pedal [4, for opening an escape valve into the sump B, in manner later to be more particularly pointed out, and allowing the hydraulic fluid to flow back into the sump.

In further accordance with the usual practice, an elongated valve strip or line in the form of a channeled body I5 is provided and is secured at its ends by screws l5a to diametrically opposite margins of the lower end of the secondary, rotatable basal section 1, This valve strip 15 is bored or channeled out axially from end to end, as at l5b, but not fully out through the ends, and is formed medially at its upper side with a threaded socket I50 for threadedly seating a stand-pipe l6, bored through from end to end as at Mia (Figure 9), this bore opening into the bore I552 of the valve strip l5. This stand-pipe i6 is provided with the usual piston-head I622, firmly anchored thereon and through which the bore lGa also extends. The usual elevator or jack tube [1 is telescopically mounted over the piston head Nib and connected with the lower jack cylinder 9 in usual manner for elevating same as the hydraulic fluid passes thereinto. The spring-set pump I2 is seated within another socket 15d formed at one end of the valve strip [5 for that purpose, and this pump communicates with the bore ISI) for drawing the oil or hydraulic fluid from the sump 8 and forcing same through the bore and up through the stand-pipe l6, and

thus hydraulically operating the chair lifting jack or mechanism as described. The opposite end of the valve strip I5 is fitted with a spring-set fluid discharge valve Hie reciprocably mounted through the bore l5j axially formed perpendicu- 4 larly down through an upstanding lug g at this end of the valve strip l5, the said bore I5f extending clear down through the bottom side of the strip 55 and having a part as shown connecting the bores 45b and I5 for the discharge of fluid into the sump 8. The lower mouth of the bore 151 is tapped for threadedly engaging ordinarily a closure plug (not shown), but for which there is substituted in accordance with this invention, a short, heavy and threaded closure screw or bolt 41, later to be more particularly described. The bore l5f is expanded diametrically at its lower end to form an annular shoulder I5h, against which the mating shoulder l5i of the correspondingly expanded lower end of the valve [5e normally closes as urged upward by its spring, the latter being of usual form and positioning. The valve 15a is also formed with a pair of spaced ports 15 i510, the same being transversely extended through the body of the valve lie, and these ports are connected by an axial duct I51. The lug 159 is formed with a discharge duct i5m, the upper end of which duct is formed with a port, as shown, which communicates with the bore 15f. Thus when the valve We is pressed downward, the lower port 15k aligns with the bore or valve line duct l5b for discharging hydraulic fluid through the vent duct 15m into the sump 3. The valve We is pressed downward by the usual operating rod- Min, and which is extended upward into the secondary basal section 1 and there supported in operative association with the inner end of the pedal I4, in the usual manner.

The foregoing structures as assembled in the form of a common type of dental chair of the kind referred to, are of course all old, and no invention is herein claimed in respect thereof.

The present invention relates to certain additions, accessories and improvements, most of which are inclosed within a separate housing 29, including a removable cover a, and which housing is designed and adapted for attachment to and upon a foot-pump dental chair such as represented at 5 in the drawing, and as above described. For the purpose of this attachment the usual cover or collar (not here shown) is removed from the upper end of the secondary basal section I, and in lieu thereof a special form of attachment collar 21 is provided for removably seating atop or over this upper end, this attachment collar constituting an essential part of the invention, and being formed with a horizontally disposable annular flange Zia for flatly overlying and embracing the upper edge of the secondary section '1 around the lower jack cylinder 9, and an integral perpendicularly pendant flan e 2112 for frictionally seating over and around the upper annular margins of the section I, to which margins it is removably secured by means of screws He entered into the conventional screw holes there provided for mounting the usual collars in operative position at and within the top end of the section '1, these screws of course being first passed through the flange 2lb, through aligned holes formed therein for the purpose.

The horizontal flange 21a of the attachment collar 2| is also formed with an elongated opening or convenience port 21d, for affording access to the interior of the unit, and this collar 2| is additionally provided and formed with a; pair of attachment ears 2| e formed with screw holes as shown, and whereby the housing 28 is remov-: able secured, snugly in place upon the pedestalof the chair, by means of set screws 22 passeddownthrough the ears 21c into the upper margin of the housing. Likewise the cover a of the housing is secured in place by screws 23 passed downv through the inner margin of the cover into the housing. The housing 2|] thus hangs suspended from the cover collar '2l, and rotates with the upper or secondary basal section 1 as the chair is used, the housing being slightly spaced from the lower, stationary basal section 6 for freedom of movement in rotating.

Within the base of the housing 20 is mounted an electric motor within a bracket 25a secured at 25b to the floor of the housing, the extended end of the motor drive shaft carrying a belt pulley 26. A gear pump 21, or any other suitable form of pump, is bracketed at 28 atop the motor 25, the extended end of the shaft thereof carrying a belt pulley 29 vertically aligned with the pulley 26 of the motor, and a belt 30 is trained over these pulleys for driving the pump 21. A flexible tubing 3| is operatively connected at one end, through a hollow coupling 32, with the pump 21, the opposite end of this tubing being extended to and connected with another tubular coupling 33, the opposite end of the latter in turn being joined to a hollow boss 34 seated through the horizontal flange 2la of the cover collar 2| adjacent one end of the port 2 Id, and opening downwardly towards the sump 8. An intake pipe 35' is connected at its upper end over the inner mouth of the boss 34, and this pipe is extended perpendicularly down into the sump 8 and has attached at its lower end a funnel-shaped strainer 35a for filtering foreign matter from the oil or other hydraulic fluid in the sump 8.

A manifold 35 is connected at one end to the delivery side of the pump 21 by means of a springset check valve 31, which permits the flow of hydraulic fluid through the pump to the manifold, but prevents its return movement or flow. A flexible deliv'ery tube 38 is connected at one end, through a hollow coupling 39, with the opposite end of the manifold 36, the other end of this tubing being extended to and connected with a tubular coupling 40, the opposite end of which coupling is joined to a hollow boss 4| seated through the horizontal flange 2Ia of the cover collar 2|, adjacent the end of the port 2ld, oppositely to the boss 34, this boss 4| likewise opening downwardly through the flange. A hollow air-dome 42 is threadedly seated on the manifold 36 by means of a tubular joint or neck 43, which said dome serves to cushion pump pulsations and jerks incidental to pumps of this kind in operation.

A delivery pipe 44 is connected at its upper end over the inner mouth of the boss 4 I, this pipe also being extended perpendicularly down to the sump 8 and being threadedly joined thereat, through a tubular elbow 45 to a specially formed valve casing 46 constituting a feature of this invention. This valve casing is designed for making the attachment of the delivery pipe 44 to the usual lifting jack devices of the chair without requiring special alterations therein and without the use of special tools or expert assistance. For this purpose the casing is chambered out interiorly to form a tapped entrance bore 46a for engaging the threaded end of the elbow 45, as at 45a, and for receiving inwardly thereof a spring-set check valve 46b. The large bore 46a opens into a series of relatively small ducts or bores 46c extended straight on out through the inner end of the casing, thus providing an end abutment 45d, against which the spring of-the spring-set valve 46b is braced for holding the valve normally closed against outward or reverse flow of the hydraulic fluid, but permitting the flow of the fluid inward therethrough. The opposite or inner end of this casing is so formed and recessed at its upper side as to closely and snugly fit, flatly and horizontally, up against the under side of the end of the valve strip [5, perpendicularly thereto in a horizontal plane, and directly under the valve l5e as reciprocably mounted in the bore [5f at that end. This fitted end of the valve casing 45 is formed with a relatively large bolt or screw hole 45c cut perpendicularly therethrough and adapted to receive and pass a short, heavy and exteriorly threaded set screw or bolt 41 bored out axially as at 41a, toward its kerfecl and laterally spread and bevelled head 41b, and having an annular channel formed there-around as at 410, immediately at the inner side of the inwardly bevelled head. The bolt 41 is also pierced diametrically by two or more bores or ducts 41d extended from the channel 410 straight through the head from side to side, said bores or ducts thus passing into and through the axial bore 41a, and thus putting the bores 41a and 41d into open communication with the channel 470. The =bolt or set screw 41 is dimensioned and threaded to exactly fit and turn up into the lower threaded mouth of the valve bore I5f, from which the standard closure plug or bolt (not shown) referred to above, has first been removed, and when this substitute bolt is fully turned up into its seat, the valve casing 46 is thereby firmly locked to the end of the valve strip I5, with the outer ends of the ducts 460 of the casing opening into the large entrance bore 46a and the inner ends thereof opening into the annular channel 470 of the bolt 41. Thus the incoming hydraulic fluid from the pipe 44 passes through the intake valve 46b, the ducts 460, the annular channel 410, the ducts 41d, the axial bore 41a, forming a port, as shown, leading into and through the conventional bore or duct l5b of the valve strip l5 into the stand-pipe I6, for operation of the lifting jack and elevator cylinders 9 and I0 thereof in usual manner. But when the discharge valve |5e is depressed 'in usual for the motor 25, the same including a horizontally extended lever arm 50akeyed as at 50b upon the inner end of a round stud 50c journaled at 50d through the rear end of the housing. 28 adjacent the base thereof.- A mercury tubeswitch 50c is mounted lengthwise on the outer end of the arm 50a, in a normally down-tilted and inoperative position and so held by means of a relatively strong coil spring 50f stretched,

vertically and secured at its ends as at 509 and 50h to the inner end of the arm 50a and at its opposite upper end to a pin set in the end of the housing, and a relatively short shock-absorbing coil spring 501' mounted on the base of the housing immediately under the outer end of the arm 50a. A pedal operating lever 5! is keyed at 5la to the outer end of the stud or stub-shaft 50c, and this lever is normally held to its up-raised and inoperative position by the spring 50f, the mercury switch 506 being thus held in downtilted, inoperative position. But it is obvious that depressing the lever 5i will result in tilting the arm 50a and mercury tube 502 oppositely, from inoperative into operative position, and so that the mercury in the tube 506 flowing to the opposite end of the tube will close electrical circuits through the contacts within that end of the tube, and thence through the motor and other electrically connected elements of the assembly, in manner later to be explained.

Likewise a similar mercury limit switch unit 55 is provided for limiting the upward travel of the chair H. This unit includes a species of leaf hinge 55a, the shorter and lower leaf 5% thereof being anchored horizontally and flatly upon the inner horizontal ledge or flange 550 as conventionally formed upon and extended circumferentially around the inner walls of the rotatable, secondary basal section i adjacent the top end'thereof, this said leaf being positioned immediately below the opening Zld of the cover collar 2|. This mounting is effected by means of a tapered screw 55d passed down through the said lower leaf 55b of the hinge 55a and into a vertically split plug 55c inserted into a hole 55 as conventionally formed at this point in the said flange 55c, whereby the partially split and parted plug 556 is spread laterally asunder against the margins of the hole 55 thus locking the leaf and hinge firmly in place atop the flange 550,

with the upper and longer leaf 55g overlying and extending out beyond the end of the lower and shorter leaf, as shown in Figure '7, and slightly tilted from the horizontal as shown. A mercury tube switch 55h is mounted lengthwise atop the upper leaf 55g and in similar tilted and consequent operative position for transmitting electrical current by virtue of the mercury in the tube closing contacts within the down-tilted end of the tube, said contacts being in turn connected with the conducting wires indicated in the drawing at Figure 7 as extended from the said tube. A stifi finger 552' is depended rigidly from the under side of the free end of the long upper leaf 55g of the hinge 55a and perpendicularly thereto, said finger being extended vertically down alongside the adjacent and vertically mounted guide-rod 5G constituting a conventional structural feature of such a chair and which is mounted at its ends adjacent an inner side of the secondary basal section I on ears (not shown) extended in vertical alignment inwardly at the top and bottom ends of the section I. This guide rod passes slidably through a lug 56:: extended outwardly at the lower end of the lower jack or elevator cylinder 9, and which lug of course moves upwardly with this cylinder 9. This lug is aligned vertically with the finger 55;,

and consequently as the lug moves upwardly in long upper hinge leaf 559 are pushed upwardly,

thus tilting this leaf and attached mercury tube 55h oppositely to their normal operative positions and to their reverse and inoperative positions as indicated in dotted lines in Figure 7, and opening the electric circuit and stopping further upward movement of the chair. stop mechanism is important should the operator forget. to release the pedal lever Si in proper time. A conventional locking lever 51 is provided for releasably locking the chair against rotation, when so desired.

This automatic that the operation and use of the invention and attachments as applied to a conventional footpump chair of the kind referred to, will be fully understood, and while we have here shown and.

described certain specific embodiments and structural features of the invention, it is to be understood that the same may be changed or modified in minor respects and details as may be desired, not departing however from the general scope of the invention as defined in the appended.

claims.

We claim:

1. The combination with a foot-operated extensible chair of the type comprising a hollow pedestal providing a sump therein for contain-' ing hydraulic fluid, a telescopicallyassembled. jack cylinder mounted in the pedestal and ar-' ranged for vertical extension therefrom, a footoperated pump unit for forcing fluid from the sump into the jack cylinder, said foot-operated pump unit including a pump, a treadle for manually operating the pump, a channeled valve strip extending from the discharge side of said foot-- operated pump and provided with a vent into the sump, said valve strip having an intermediate standpipe leading to the jack cylinder, a fluidescape valve positioned in the valve strip between the standpipe and said vent to the sump, and a laterally opening threaded bore in line with said' fluid-escape valve; pump unit comprising a motor-driven pump having its inlet side communicating with said sump, a delivery line between the discharge side of the motor-driven pump and the valve strip, a valve casing connecting said delivery line and the laterally opening bore of said valve strip and having a check valve movable to open position by the flow of fluid from the delivery line to the valve strip, and a bolt passing through said valve casing and threadedly engaging said valve strip bore for securing the valve casing to the valve strip, said bolt being axially recessed to provide a fluid passageway between the valve casing and said valve strip and said motor operated pump unit being vented to said sump by said fluid-escape valve of said foot-operated pump unit. I

2. The combination with a foot operated extensible chair of the type comprising a hollow;

pedestal providing a sump therein for containing hydraulic fluid, said pedestal having an upper rotatable part and a lower stationary part, a

telescopically-assembled jack cylinder mounted in the pedestal and arranged for vertical extension therefrom, a foot operated pump unit for forcing fluid from the sump into the jack cylinder, said foot-operated pump unit including a pump, a treadle for manually operating the pump, a channeled valve strip extending from the discharge side of said foot-operated pump,- and provided with a vent into the sump, said, valve strip having an intermediate standpipe, leading to the jack cylinder, a fluid-escape valve, positioned in the valve strip between the stand pipe and said vent to the sump, and a laterally 3 opening bore intermediate the standpipe and of a motor-operated i said vent to the sump; of a motor-operated pump unit comprising a motor-driven pump having its inlet side communicating with said sump, a delivery line between the discharge side of the motor-driven pump and the valve strip, a valve casing connecting said delivery line and the laterally opening bore of said valve strip and having a check valve movable to open position by the flow of fluid from the delivery line to the valve strip, an attachment collar removably mounted on the upper rotatable part of the pedestal and rotatable therewith, a housing for said motor-operated pump unit supported solely by the collar in closely-spaced relation to the lower stationary part of the pedestal, and a removable cover closing a side of the housing, said motor-operated pump unit being vented to said sump by said fluid-escape valve of said footoperated pump unit.

3. An attachment for a chair having a pedestal, a sump in said pedestal, hydraulic cylinder elevating mechanism comprising a channeled valve strip connected to said mechanism, foot-operated pump means for supplying fluid under pressure from said sump to said valve strip for operating said mechanism, and valve means for venting said valve strip to said sump, said valve strip having a threaded bore communicating with the channel thereof and opening outwardly through a side of said strip, said attachment comprising an electric motor and pump unit for operating said mechanism, a connection between the intake port of said motor-driven pump and said sump, a connection between the delivery port of said motor-driven pump and said valve strip including a channeled valve casing having a bore communicating with the channel thereof and opening outwardly through opposite sides of said casing, and a threaded bolt passing through the bore of said casing and engaging the bore of said valve strip for securing said casing and valve strip together with said bores thereof in communication with each other, said bolt having a channel therein for connecting the channels of said casing and valve strip, a check valve in said connection, and means for controlling the operation of said motor.

4. An attachment for a chair having a pedestal, a sump in said pedestal, hydraulic cylinder elevating mechanism having an upper rotatable pedestal portion open at its top, said mechanism comprising a channeled valve strip connected thereto, foot-operated pump means for supplying fluid under pressure from said sump to said valve strip for operating said mechanism, and valve means for venting said valve strip to said sump, said valve strip having a bore communicating with the channel thereof and opening outwardly through a side of said strip, said attachment comprising an electric motor and pump unit for operating said mechanism, a connection between the intake port of said motor driven pump and said sump, a connection between the delivery port of said motor driven pump and said valve strip including a channeled valve casing having a bore communicating with the channel thereof and opening outwardly through a side of said casing, means for securing said casing and valve strip together with the bores thereof in communication with each other, a check valve in said connection, a mounting ring secured to said rotatable pedestal portion and closing said top of said pedestal portion, said electric motor and pump unit being secured to said ring for rotation therewith, and means for controlling the operation of said motor.

5. An attachment as specified in claim 4 in which the delivery port of said motor driven pump is provided with a connection to said valve strip including a channeled valve casing having means for securing the same to said valve strip with said bores thereof in communication with each other and a check valve is interposed in said connection to prevent the transmission of fluid therethrough from said valve strip.

ELI P. SCHWARTZ. CHARLES W. MEYER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,887,328 Russell Nov. 8, 1932 1,959,682 May May 22, 1934 2,063,122 Richardson Dec. 8, 1936 2,215,666 Meitzler Sept. 24, 1940 2,253,597 Wyne Aug. 26, 1941 2,352,678 Angell July 4, 1944 

